How to avoid async function in promise executor

Question

I am trying to understand Promises in Javascript. I have a situation where my code has some "nested" promises, and when installing ESLint I was made aware that async functions in Promise executors is considered an anti-pattern. I have code along the lines of:

const main = (indata) => {
  heavyOperation(indata).then( (res) => {
    console.log(res);
  }).catch( err => {
    console.err(err);
  }).finally( () => {
    cleanUp();
  }
}

async const heavyOperation = (indata) => {
  return new Promise( (resolve, reject) => {
    preProcess(indata);
    try {
      const result = await calculate(indata);
    } catch (err) {
      console.err('Error in calculation.');
      reject(err);
    }      
    const processedResult = postProcess(result);
    resolve(processedResult);
  }
}

const preProcess = (indata) => { 
  //preprocessing
}

async const calculate = () => {
  // do stuff
}

const postProcess = (result) => { 
  //postprocessing
}

main(indata);

How can I refactor this code? Should I get rid of heavyOperation returning the promise entirely? How can I then achieve the .then , .catch , .error functionality?

Answer 1

在这种情况下，尝试使用Promise chaining 。